Tunnelling machines

ABSTRACT

A tunnelling machine, more particularly but not exclusively intended to operate in soft ground, comprises a tubular cutting and protection shield which is periodically advanced with reference to a base or an already erected section of tunnel lining and is preferably characterized by the provision at the forward end of the shield of a pair of cutter-carrying excavating jaws which are power operated and swingable in arcuate excavating paths about parallel axes from retracted positions inside the shield to positions projecting forwardly thereof wherein the jaws are closed upon one another.

United States Patent 1 Mazzotti s 541 TUNNELLING MACHINES Peter Charles Mazzotti, l-lindhead, Surrey, England [73] Assignee: Streeters Plant Hire Limited,

Godalming, Surrey, England [22] Filed: Jan. 25, 1971 [21] Appl. No.: 109,496

[75] Inventor:

[30] Foreign Application Priority Data June 17, 1970 Great Britain ..29,347/70 [52]. US. Cl ..299/33, 299/85 [51] Int. Cl ..E0lg 3/03 [58] Field of Search ..299/31, 33, 67, 71, 85, 86

[56] References Cited UNITED STATES PATENTS 752,931 2/l904 Smith ..299/3l X [451 Jan. 16, 1973 9/1932 Hughes ..299/71X 5/1969 Lauber ..299/7IX Primary Examiner-Ernest R. Purser Attorney-Beehler & Arant [5 7] ABSTRACT A tunnelling machine, more particularly but not exclu sively intended to operate in soft ground, comprises a tubular cutting and protection shield which is periodically advanced with reference to a base or an already erected section of tunnel lining and is preferably characterized by the provision at the forward end of the shield of a pair of cutter-carrying excavating jaws which are power operated and swin'gable in arcuate excavating paths about parallel axes from retracted positions inside the shield to positions projecting for wardly thereof wherein the jaws are closed upon one another.

6 Claims, 7 Drawing Figures PATENTEDJAH 16 1975 SHEET 1 BF 5 m s m m T W m O A T VH T W A R E T W VI B PATENTEUJAH 18|975 3.711.159

SHEET 2 OF 5 INVENTOR PETER CHARLES MA'LlOTT-l ATTORNEY PATENTEDJAHB I975 3.711.159

SHEET 5 [IF 5 FIG. 5.

Q J, FIG. 6. q T

FIG. 7

Ev /r/er Ar in ATTORNEYS TUNNELLING MACHINES This invention relates to tunnelling machines of the kind which are more particularly but not exclusively intended to operate in soft ground and which usually comprise a tubular cutting and protection shield which is periodically advanced with reference to a base or an already erected section of the tunnel lining.

Relatively large'machines of the kind referred to are commonly provided with a rotary cutter or excavator which is co-axial with the shield and some form of mechanical conveyor is provided for removing the spoil.

Such machines are expensive and not usually justified, or available, for cutting relatively small diameter tunnels having a diameter of the order of for instance 6 feet. In consequence small bore tunnelling machines usually only comprise a cylindrical shield with a cutting edge, excavation and spoil removal being effected manually there being only a relatively small space available for any extra cutter and/or mechanical conveyor. The cutting rate of such machines is therefore inevitably slow, particularly in wet ground, and the cost of manual labor is high.

The object of the invention is to provide a more efficient and rapid tunnelling machine particularly but not necessarily of relatively small size having improved and relatively inexpensive excavating means which occupies less space within theshield and which facilitates installation of a spoil removal conveyor.

In accordance with the present invention therefore a tunnelling machine of the kind referred to comprises at the forward end of the shield .a pair of excavating, cutter carrying, pivoted jaws which are power operated and movable towards and away from one another to excavate the material ahead of but within the confines of the cutting edge of the shield.

A particular and at present preferred form of tunnelling machine incorporating the invention is illustrated in the accompanying drawings and will hereinafter be described by way of non-limitative example. A

In these drawings:

FIG. 1 is a fragmentary isometric view of the forward end of the tunnellingmachine;

FIG. 2 is a frontal elevation of the tunnelling machine; 7

FIG. 3 is a section on line A-A of FIG. 2;

F IG. 4 is a section on line B-B of FIG. 2; whilst FIGS. 5, 6 and 7 illustrate different excavating jaw formations for alternative tunnel shapes.

Referring now to the v drawings, the tunnelling machine shown in FIGS. 1 to 4 comprises a cylindrical shield l with a front cutting edge 2 situated in a diametric plane. The shield 1 is equipped internally with two or more main thrust rams 3 which operate between an internal annular abutment flange 4 forming part of the shield and the leading end parts 5 of an already inserted tunnel lining section. The latter may for instance be comprisedof arcuate concrete sections. The rams are hydraulically operated and periodically advanced, retracted and adjusted in the usual manner.

Just. inside the cutting end of the shield a pair of semi-circular excavating jaws 6, 6' are mounted on individual parallel shafts 7 situated one each side of and perpendicular to the center axis of the shield. These shafts 7 are normally vertical and when the jaws 6, 6' are fully open they lie in a diametric plane and concentrically adjacent the inside surface of the shield 1. In FIGS. 1 to 4 the excavating jaw 6 is shown in such a position. The excavating jaws 6, 6' carry a series of forwardly directed digging teeth 8 dimensioned and spaced to suit ground conditions. Alternatively discs or other cutters could be fitted.

In their fully closed positions the jaws 6, 6' project I forwardly of the shield 2 and lie in planes parallel with the shield axis with the teeth 8 in engagement. In the drawings the jaw 6' is shown in such a position. The jaws are swung in unison between their fully open and fully closed positions by simultaneous extension of individual hydraulic rams 9 pivotally anchored within the shield and each pivotally connected to a frame portion 10 of a jaw intermediate its pivoted and its outward end. The jaw operating rams 9 would operate from the same hydraulic circuit as the main thrust rams.

In operation after each operation of the thrust rams 3 to cause further advance of the shield 1 into the ground, the other rams 9 are operated to close the jaws 6, 6' together. This closing movement causes the cutting teeth 8 on the jaws to scoop vor excavate a part spherical mass of material which is removed as spoil either manually or preferably by means of a small self loading endless belt ordrag bucket conveyor (not shown) operating longitudinally within the shield l.

The excavating jaws 6, 6' and the rams 9 for operating them are preferably mounted so as to facilitate case respectively. In these Figures, the positions of the hydraulic rams are indicated by circles and it is to be noted that in FIG. 6 the jaws pivot about horizontal axes.

In contrast with known tunnelling machines there is no tendency with the improved machine for the shield to rotate during cutting operations and in general the design of the machine is simple thereby resulting in low cost.

Although the improved tunnelling machine is particularly intended for relatively small bore soft ground tunnelling, there appears to be no reason to suppose that the improved machine could not be commercially competitive inlarger sizes or be used also for tunnelling in relatively hard ground using differently designed cutters if necessary.

I claim:

- 1. A tunnelling machine comprising:

a cylindrical shield with a front cutting edge situated in a diametric plane;

a pair of arcuate, swingable jaws, said jaws when open lying in a diametric plane inside and adjacent jaws may swing to a closed position in which they extend parallel to each other in front of said shield;

each of said jaws having a centrally located operating arm which extends perpendicular to the plane of the jaw;

a pair of hydraulic drive cylinders having their forward ends coupled to corresponding ones of said operating arms, and having their rearward ends pivotally supported adjacent corresponding portions of the shield wall; and

said jaws being provided with teeth for cutting the earth.

2. The tunnelling machine claimed in claimv 1 wherein said pivot means support said jaws ends on a pair of spaced, parallel axes, one for each jaw.

3. A soft ground tunnellingmachine comprising a tubular shield with a front cutting edge, at least one swingable jaw shaped to match part of the interior profile of said shield and having teeth on the front edge thereof, pivot means supporting said jaw so as to enable -to the axis of said shield and respectively supporting said jaw to turn in an arcuate path from a position in said jaws so as to enable said jaws to turn in arcuate the shield and positions in which they project forwardly thereof with their teeth closed together so as to excavate the ground, and hydraulic means mounted within said shield and coupled to said jaws for causing them to move in said arcuate paths.

5. A tunnelling machine comprising a tubular cutting and protection shield having in its forward end an excavatin'g head comprising a pair of cutter-carrying excavating jaws which are power operated and swingable in arcuate excavating paths about parallel axes from retracted positions inside the shield to positions projecting forwardly thereof wherein the jaws are closed upon one another;

wherein said excavating jaws are mounted from first flanged parts of the shield and are operable by individual, hydraulic rams anchored to second flanged parts of the shield.

6. A tunnelling machine comprising a tubular cutting and protection shield having in its forward end an excavating head comprising a pair of cutter-carrying excavating jaws which are power operated and swingable in arcuate excavating paths about parallel axes from retracted positions inside the shield to positions projecting forwardly thereof wherein the jaws are closed upon one another; v

and further comprising main hydraulic thrust rams operable between an internal flanged part shield and a rearward abutment.

of the" 

1. A tunnelling machine comprising: a cylindrical shield with a front cutting edge situated in a diametric plane; a pair of arcuate, swingable jaws, said jaws when open lying in a diametric plane inside and adjacent to said front cutting edge of said shield; pivot means supporting the ends of said jaws from the corresponding sides of said shield, so that said jaws may swing to a closed position in which they extend parallel to each other in front of said shield; each of said jaws having a centrally located operating arm which extends perpendicular to the plane of the jaw; a pair of hydraulic drive cylinders having their forward ends coupled to corresponding ones of said operating arms, and having their rearward ends pivotally supported adjacent corresponding portions of the shield wall; and said jaws being provided with teeth for cutting the earth.
 2. The tunnelling machine claimed in claim 1 wherein said pivot means support said jaws ends on a pair of spaced, parallel axes, one for each jaw.
 3. A soft ground tunnelling machine comprising a tubular shield with a front cutting edge, at least one swingable jaw shaped to match part of the interior profile of said shield and having teeth on the front edge thereof, pivot means supporting said jaw so as to enable said jaw to turn in an arcuate path from a position in which it is retracted within the shield to a position in which it projects forwardly thereof so as to excavate the ground, and hydraulic means mounted within said shield and coupled to said jaw for causing said jaw to move in said arcuate path.
 4. A soft ground tunnelling machine comprising a tubular shield with a front cutting edge, a pair of swingable jaws shaped to match respective halves of the interior profile of said shield and having teeth on the front edges thereof, pivot means offset from and transverse to the axis of said shield and respectively supporting said jaws so as to enable said jaws to turn in arcuate paths from positions in which they are retracted within the shield and positions in which they project forwardly thereof with their teeth closed together so as to excavate the ground, and hydraulic means mounted within said shield and coupled to said jaws for causing them to move in said arcuate paths.
 5. A tunnelling machine comprising a tubular cutting and protection shield having in its forward end an excavating head comprising a pair of cutter-carrying excavating jaws which are power operated and swingable in arcuate excavating paths about parallel axes from retracted positions inside the shield to positions projecting forwardly thereof wherein the jaws are closed upon one another; wherein said excavating jaws are mounted from first flanged parts of the shield and are operable by individual hydraulic rams anchored to second flanged parts of the shield.
 6. A tunnelling machine comprising a tubular cutting and protection shield having in its forward end an excavating head comprising a pair of cutter-carrying excavating jaws which are power operated and swingable in arcuate excavating paths about parallel axes from retracted positions inside the shield to positions projecting forwardly thereof wherein the jaws are closed upon one another; and further comprising main hydraulic thrust rams operable between an internal flanged part of the shield and a rearward abutment. 